The present invention relates to a surgical microscope used in the medical field.
In general, surgical microscopes are used for surgical operations in cerebral surgery, otolaryngology, ophthalmology, and the like, and play an important role, i.e., improving the efficiency of surgical operations by allowing observation of regions under magnification. In addition, in recent years, to perform surgical operations more reliably, endoscopic observation is also performed in conventional surgical operations which have been performed under observation with surgical microscopes. Demands have therefore arisen for techniques of allowing an operator to simultaneously observe a surgical microscopic observation image and an endoscopic observation image within the visual field of a surgical microscope. Demands have also arisen for simultaneous observation of information such as a CT or MRI image before a surgical operation and nerve monitor information during the operation as well as an endoscopic observation image.
In order to meet such demands, a technique of allowing an operator to simultaneously perform observation with a microscope and observation with a second observation means within the visual field of the microscope is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 62-166310. That is, a means for simultaneously guiding an optical image from a stereoscope and a monitor image from an endoscope to the same eyepiece optical system and displaying the sensed images such as an endoscopic image on the eyepiece portion of the stereoscope is disclosed.
A means for displaying data on the eyepiece portion of a stereoscope or the like is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 63-167317. More specifically, a technique of projecting the exit pupil of a data image on a portion outside the exit pupil of a microscopic image by applying a light beam such as data light from the outside of a main observation light beam such as a microscope light beam is disclosed.
In addition, a technique of realizing simultaneous observation with a microscope and an endoscope is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 3-105305. More specifically, a means for projecting the optical image or electronic image obtained by a 2D endoscope onto the eyepiece portion of a stereoscope, a means for guiding a 2D endoscopic image to the right and left optical paths of the microscope, and a member for shielding a microscope light beam are disclosed.
A means for displaying an endoscopic image or the vital data of a patient within or near the visual field of a microscope is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-140991. More specifically, a technique of guiding an endoscopic image or the like into the visual filed of a microscope through a half mirror, a technique of displaying a microscopic image and an endoscopic image within the same visual field by guiding a microscope optical path and an endoscope optical path to an eyepiece lens in a parallel state (see FIG. 3 in this reference), and the like are disclosed.
According to the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 62-166310, however, when the image obtained by the monitor optical system is to be observed outside the optical image obtained by the microscope optical system, since the field stop of the microscope interferes with the observation, the monitor image is vignetted or the field stop of the microscope must be removed. Assume that the field stop of the microscope is removed. In this case, when only the microscopic image is to be observed, since no field stop is placed in the area where the monitor image is to be projected, even an image outside the image circle formed by the microscope optical system can be seen. For this reason, the operator must always observe even a peripheral image with poor image quality, and hence suffers from unnecessary fatigue as the image quality deteriorates. According to the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 62-166310, part of the visual field of the microscope is shielded by the reflecting member placed near the imaging plane of the microscope. For this reason, when this shielded portion is to be observed, the overall microscope must be moved to move the observation point out of the shielded portion of the visual field of the microscope. The movement of the overall microscope interrupts a surgical operation and reduces the operation efficiency. In addition, in this reference, the positional relationship between the imaging plane of the microscope and the reflecting member is not clarified. When, therefore, the center of the reflecting member is positioned on the imaging plane of the microscope as shown in the drawing, the upper and lower portions of the reflecting member are separated from the imaging plane of the microscope to cause defocusing. As a result, the boundary between the visual field of the microscope and the image (the image obtained by the second observation means and put in the visual field of the microscope by the reflecting member) cannot be clearly discriminated.
According to the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 3-105305, since a microscopic image and an endoscopic image are superimposed on each other within the same visual field (the microscopic image and the endoscopic image are coupled to each other by the half mirror), each image cannot be observed in detail unless one of the image light beams is shielded. It is therefore difficult to simultaneously observe a microscopic image and an endoscopic image within the visual field of the microscope while orientating the endoscope. In addition, since the endoscopic image is always superimposed on the entire microscopic image, the operator cannot concentrate on operation under the microscope.
Furthermore, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-140991, according to the technique of guiding the microscope optical path and the endoscope optical path to the eyepiece lens in a parallel state, since the endoscope optical path is positioned outside the microscope optical path and cannot be inserted/withdrawn into/from the microscope body, no field stop is formed at a portion corresponding to the endoscope optical path even if endoscopic observation is not required. For this reason, as in the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 62-166310, an image outside the image circle of the microscope optical system can be seen.
When an endoscopic image is to be observed, it is required that a monitor image be observed while the image is enlarged to the maximum size to be easily seen. In this case, however, since the microscopic image inevitably decreases in size, this technique is not so practical.